Valve for road sanding machines



Nov. 16, 1943. R. R. ELSTON VALVE FOR ROAD SANDING MACHINES Filed Jan.14, 1942 Patented Nov. 16, 1943 VALVE FOR ROAD SANDING MACHINES Rue R.Elston, Minneapolis, Minn, asslgnor to Highway Safety Appliances,Incorporated, St. Paul, Minn., a corporation of Minnesota KpplicationJanuary 14, 1942, Serial No. 426,736

3 Claims. -(Cl. 291-23) This inventlon'relates to valves for controllingthe flow of sand from a hopper, the device being particularly adaptedfor use on vehicles to control the sanding of the road or track in frontof the vehicle wheels.

It is my object to minimize the power consumed in the operation of avalve of this class and also to insure uniformity and certainty ofoperation of the valve against varying heads of sand in a reservoir orhopper by a novel arrangement of valve seat in a sand passage.

The invention will be best understood by reference to the accompanyingdrawing in which:

Figure 1 is a part central vertical section and part front elevationillustrating my improved-arrangement of the valve in a sand passageextending from a hopper-to the discharge spout of a road sandingmachine;

Fig. 2 is a side elevation of the same;

Fig. 3 is a horizontal section taken on the line 3-3 oi Fig. 1, and

Fig. 4 is a vertical section through the valve casing illustrating theflow of sand therethrough.

In the machine illustrated in the drawing, a sand reservoir or hopper 4is provided at the top with a removable filling cap 5 and at the bottomwith an outlet opening 6. From the opening 6 sand flows by gravity intoa conduit formed by a casting I having branch passages 8 communicatingwith flexible rubber outlet nozzles 9. The machine is so located on themotor vehicle that the sand discharged from the nozzles 9 is deliveredto the road'directly in front of the vehicle traction or driving wheels.When used on vehicles having double tires, as on large trucks, bussesand trailers, a pair of the nozzles 9 are provided, as illustrated,otherwise a single discharge nozzle is provided for each valve.

The flow of sand from the opening 6 into the branch passages 8 iscontrolled by a valve having a head ID of conical shape mounted on ahorizontally disposed plunger II. This plungerv istry with and equal insize to the opening 6. This has the effect of limiting the flow of sandto the horizontally offset valve seat. Thehorizontal offset of the seat,indicated by the dimension A, from the opening 6 and the restrictedpassage above the seat is an important feature of my invention as itminimizes the pressure exerted by the sand in opposing the closing ofthe valve and also allows free flow of the sand to discharge. I havefound that for the best results the dimension A should not be large. Itis, preferably, about one-half inch for most installations.

, A helical spring M is mounted on the plunger II or valve stem and isconfined between an end of the solenoid and a collar on the valve stemso that the spring actuates the valve to closed position. When thesolenoid is energized, the plunger II is drawn against an adjustablestop l5 to open the valve.

When the valve is opened against the action of the spring H the sandflows from the opening 6 obliquely downward and horizontally over thevalve seat so that the upper surface of the sand extends approximatelyalong the dotted line B, leaving a small empty space C near the top ofthe .valve seat, and beneath the overhanging edge of the hopper. Whenthe circuit to the solenoid I2 is broken, the spring l4 quickly closesthe'valve. In this operation it is unnecessary to lift an appreciablequantity of sand back into the hopper and it is only necessary todisplace a small amount of it into the empty space C immediately ismovable axially in a solenoid coil I2 for which power is supplied fromthe vehicle battery through an electric circuit under control of anelectric switch (not shown). An annular seat I 3 for the valve head I0is formed in the castadjacent to the valve seat.

Conservation of electric power is particularly important in motorvehicles where increasing demands for electrical accessories have atendency to overload the vehicle batteries. As the power required toopen the valve head ill need be' only sufficient to compress the springI 4, it has been found in practice that my horizontally movable valverequires but a small fraction of the power necessary to close a similarvalve operating vertically against a head of sand. It has also beenfound that the power required to operate my improved valve issubstantially uniform irrespective of the head of sand in the hopper andthat more positive,v reliable and uniform action of the valve isinsured.

Having described my invention, what I claim as new and desire to protectby Letters Patent is:

1. In a sanding machine of the class described, the combination of asand reservoir having an outlet opening communicating with the bottomthereof, a conduit having a discharge passage in the direction of flowof sand in said passage to exclude sand from the upper portion of saidseat, a substantially horizontally movable valve the direction of flowof sand in said passage, an

annular valve head movable substantially horizontalLv and counter to theflow of sand in said passage to engage said seat and electrical meansfor operating said head substantially horizontally to control the flowof sand through said passage.

3. In a sanding machine of the class described,

the combination of a sand reservoir having an outlet opening, a conduithaving a discharge passage communicating with said opening and extendinghorizontalLv and downward therefrom,

head adapted to be moved counter to the flow of sand in said passage toengage said seat and electrical means for operating said valve headsubstantially horizontally to control the flow of sand through saidpassage.

2. In a sanding machine of the class described,

the combination of a sand reservoir having an outlet opening in thebottom thereof, a conduit having a discharge passage communicating withsaid opening and extending horizontally and downward therefrom, asubstantially vertically disposed valve seat in said passage, thehorizontal cross sectional area of said passage at .its upper end beingnot larger than the cross sectional area thereof adjacent to said seat,said seat being 'otfset horizontally from said outlet opening in anannular, substantially vertically disposed valve seat in said passage,said passage being restricted above said seat to limit the flow of sandto said seat and said seat being ofiset substantially from saidreservoir opening in the direction of flow. of sand in said passage toexclude sand from the upper portion of said seat, a conical valve headmovable substantially-horizontally to engage said seat at the efliuentside thereof; the apex of said head projecting in a direction counter tothe flow of sand in said passage beyond said seat, a spring normallytending to close said head against said seat and electrical means foroperating said head substantially horizontally to open the valve.

RUE R. ELSTON.

